1. Field of the Invention
The present invention relates to an ostomy coupling of the kind comprising a first and a second annular coupling part and a locking ring, where one of the coupling parts is secured to a self-adhesive plate or disc by which it is attachable to the ostomy patient around his stoma, and where the other coupling part carries a collection receptacle or closing plug, and where the locking ring is intended for holding together the first and the second coupling part in tight and secure contact with each other.
2. Description of Related Art
In the following an ostomy patient or ostomist means a person who has a colostomy, an ileostomy or an urostomy. In such persons a projection of the colon, ileum or urethra has been performed surgically, so that the body's waste products passing through these organs are discharged through an artificial opening, and are collected continuously or at intervals in a collection receptacle, such as a foil bag. If the collection is performed at intervals, the collection receptacle may in the intervening periods be replaced by a closing plug, as known e.g. from DK patent specification No. 153 122.
The collection bag or the closing plug may be attached directly around the stoma by means of an adhesive disc, but since these parts must be changed even several times daily, and since frequent removal of such an adhesive disc from the skin may cause extreme damage thereto, use is generally made of two-part ostomy equipment consisting of an adhesive disc which is attachable around the ostomist's stoma, and on the non-adhesive surface of which an annular coupling part is attached, often called a plate coupling part, which can be coupled to another annular coupling part which carries a collection receptacle or a closing plug.
Since it is extremely important that such ostomy couplings are tight and secure against unintended removal, it calls, however, for quite large axial pressure force to couple them together, and a large axial pulling force to separate them again. Since the skin area around a stoma is often very tender, recent years have seen the development of ostomy couplings which can be coupled together and separated with reduced axial force impacts.
In this connection it should be observed that by axial pressure and pulling forces are meant forces which in the mounting and demounting situation influence the skin area around the stoma with pressure and pull, respectively. Similarly, by statements of axial direction are meant directions which are essentially parallel to the center axis of the coupling parts. The axial thickness of a coupling ring or locking ring thus denotes the distance between two planes which are perpendicular to the center axis and intersect the surface or line on the coupling or locking ring which in a use situation is closest to the user's stoma-surrounding skin surface and remotest from the user's stoma-surrounding skin surface, respectively.
A coupling of the above kind is known e.g. from EP patent specification No. 347 025. The ostomy coupling disclosed therein consists of two annular coupling parts, one of which is attached to an adhesive disc for attachment around a stoma, and the other carries a collection bag, and a locking ring which locks together the two coupling parts. The two coupling parts each have a closed loop-form, i.e. that in their annular extension they stretch a distance in axial direction away from the adhesive disc or the collection bag, respectively, and deflect in radial outward direction. The part on the first and the second coupling part, respectively, which stretches radially outwards, has plane surfaces. In the coupling situation the outer plane surfaces facing away from the adhesive disc and the bag, respectively, to which they are attached, are placed against each other, whereafter they are squeezed together by means of a locking ring having U-shaped cross-section, the locking ring embracing the two radially projecting parts of the coupling parts in their entire annular extension. This ostomy coupling is consequently lockable without any use of axial force impacts, since the two coupling parts are held together by the locking ring alone.
A similar ostomy coupling is known from WO published specifications No. 91/01118 and 91/01119. The ostomy coupling therein disclosed differs from the one mentioned above in having a primary and a secondary coupling mechanism, and in the two coupling parts not having plane contact surfaces. The two coupling parts each have projecting parts being capable of passing into mutual engagement so as to form a primary tight assembly of the coupling parts. This primary coupling together and uncoupling thereof calls for moderate axial pressure and pulling forces. For psychological reasons and in consideration of any extreme load, another locking ring with U-shape is positioned around the coupling part. This locking ring which constitutes the secondary coupling mechanism, embraces the radially projecting parts of the two coupling parts without, however, necessarily having a squeezing effect thereon. The secondary coupling mechanism will thus not be loaded under normal circumstances, but only in case of a substantial pull in the bag part.
The locking rings described above must, however, necessarily have a certain axial thickness, since the locking rings have two annular radially inwardly projecting legs or protrusions for enclosing the annular radially outwardly projecting parts of the two coupling parts. In view of material strength and manufacturing tolerances there is thus a lower limit for the axial thickness of the coupling.
It is of great importance to ostomy patients that the ostomy equipment is as invisible as possible, and that it can be hidden under the clothing. Even the smallest reduction in axial thickness will therefore have great phychological importance.
GB patent specification No. 2 215 212 discloses an ostomy coupling consisting of two coupling parts and a locking ring, which only has one annular radially inwardly projecting protrusion. One of the coupling parts is of a deformable material and is, as described above, attached to an adhesive disc which projects outwardly therefrom in a closed loop-form so as to form a collar having an annular groove. The other annular coupling part is attached to a collection bag and extends outwardly therefrom in axial direction, and is furthermore provided with a small annular beak. The two coupling parts are assembled by one deformable coupling part being positioned in radial direction over the other, so that the beak in the second coupling part engages with an annular recess in the deformable one coupling part. This engagement between the beak and the recess has in itself no significant strength because of the flexible property of the deformable material. The locking ring is thereafter positioned in the annular edge, whereafter it is locked and thereby squeezes the deformable coupling part against the other coupling part.
This last described ostomy coupling may thus be shaped with a smaller axial thickness than ostomy couplings where the locking ring has two annular radially inwardly directed legs or protrusions which in the coupling situation are to embrace and hold or squeeze together radially outwardly projecting parts on the two coupling parts.
The functional basis of the ostomy coupling according to GB patent specification No. 2 215 212 is, as described above, deformation of the coupling material. Such deformation, however, results only in a very small radial engagement and consequently provides only limited strength against unintended tearing off. Even in such cases where the locking ring exerts considerable force on the deformable material, the radial engagement will be very small, and at the same time this will entail that substantial finger strength is required for locking the locking ring.
This is very inexpedient since many ostomy patients are elderly people with little finger strength and/or failing motorics. Furthermore, the force impact of the locking ring on the deformable material will propagate to the in radial direction innermost coupling part, whereby the latter may easily break.